Repairing and heating the molds

After the burn out, the molds are removed and inspected. Notice how the molds are now white. Very often small cracks and less frequently huge cracks are found in the molds. Cracks appear for many reasons: the mold was too thin in a section, there is a stress point or simply because it was dropped or banged up against something. The molds are very carefully inspected for even the smallest cracks because when the melted bronze is poured into it, the entire mold may break. All cracks are repaired with cement and fiberglass. In the molds in the back of the photo, you can see molds with gray. The gray is the color of the cement repair. The students slab on the cement, wrap the crack with fiber glass strips then put on more cement. We do the burn out the day before a bronze pour so there will be time to do the repairs.
After the molds are all inspected and repaired, they are placed in a kiln to heat before the melted bronze can be poured into them. Sometimes additional cracks form in this second heating and if so we repair them again.